American champion and longtime sire in Japan Boston Harbor passed away from old age March 9, according to Shigeki Yusa, stallion affairs manager for Japan Bloodhorse Breeders Association.

“We are truly saddened to lose him and are grateful for all the support from his fans over the years,” Yusa posted on Twitter March 11 about the 27-year-old son of Capote out of the Vice Regent stakes winner Harbor Springs.

Boston Harbor was a brilliant 2-year-old. He won six of seven starts as a juvenile, winning his debut May 25 at Churchill Downs. He became a graded stakes winner in his second start after capturing the G3 Bashford Manor Stakes and then suffered his only loss of the year in the G3 Sanford Stakes  to Hobeau Farm homebred Kelly Kip, trained by Allen Jerkens, on a muddy Saratoga Race Course track. Boston Harbor would not lose again that year, stringing together four consecutive stakes victories that included the G2 Breeders’ Futurity at Keeneland and the G1 Breeders’ Cup Juvenile.

Boston Harbor’s stud career did not start in blazing fashion, he ranked 14th on the 2001 freshman sire list, so before the end of 2001 he’d been sold to the JBBA. He would fashion a useful stud career in Japan with 90% of his foals making it to the races and 63% becoming winners. The best of his elite runners, however, would come from his first four U.S.-bred crops. They included grade 1 winner and four-time graded stakes winner Healthy Addiction, grade 2 winners Boston Common and My Boston Gal, and grade 3 winners Boston Bull and Mauk Four.